Automated tomato harvesting is well known, and tomato harvesting machines are in widespread use. U.S. Pat. Nos. 3,390,768 and 4,091,931 are representative of tomato harvesters that are presently in commerical use. In operation, an automatic tomato harvester first severs the tomato vines from the ground and delivers the tomato-bearing vines upwardly and rearwardly on an inclined conveyor (elevator) to a shaker unit where the tomatoes are separated from the vines. The vines are discarded, typically by being discharged onto the ground, and on one comercially available harvester the separated tomatoes fall onto transversely extending cross conveyors which carry them outwardly to longitudinally extending sorting belts located along each side of the harvester. The longitudinally extending sorting belts carry the tomatoes rearwardly with respect to the harvester's direction of travel, and workers positioned therealong screen the tomatoes to remove rotten, overripe, or underripe tomatoes as well as foreign objects such as dirt clods and vine fragments.
In order to reduce the required number of workers, improvements directed to automatically rejecting culls and foreign objects have been developed, as for example in the above referenced U.S. Pat. No. 4,091,931. However, regardless of whether the tomatoes have been sorted by manual labor and/or automatic means, they pass rearwardly onto a transversely moving rear sorting belt where they are finally inspected prior to being delivered on an unloading elevator for discharge into large bins or bulk trucks being transported alongside the harvester.
Tomato harvesters of the above described type have found widespread acceptance and enjoyed considerable commercial success for the harvesting of so-called "process" tomatoes. These are ripe tomatoes which, upon being harvested, are immediately transported to nearby food processing plants for cooking and canning or bottling in the form of one of a number of processed tomato products. Since the harvested tomatoes are generally ripe, the emphasis on harvester design has been to avoid handling the tomatoes in such a way that puncturing the skin is likely to occur. Bruising and abrasion that do not result in a puncturing of the skin, while not particularly desireable, are not serious problems since appearance of the harvested tomatoes is not a major factor. While such occurrences do tend to cause premature spoilage, a long shelf life of the harvested product is not critical due to the substantially immediate processing that is carried out.
Unfortunately, harvesters of the above described type have generally proved unsuitable for automatically harvesting so-called "fresh market" tomatoes. These are tomatoes destined to be purchased by the consumer in their raw state. Fresh market tomatoes are usually harvested in a green state and maintained in cold storage for a period of several weeks until shipment to the produce market. Therefore, fresh market tomatoes must not be bruised or abraded, since appearance in the market is an important consideration to consumers, and since abrasion and bruising tend to cause premature spoilage. Therefore, reliance has been on the costly, tedious, and often undependable method of manual harvesting. A further requirement, namely that the harvested tomatoes be above a predetermined minimum size, further favors hand harvesting of fresh market tomatoes. Thus, while advances in the automated harvesting field have permitted growers of process tomatoes to realize greater crop yields per acre at lower costs, these benefits have been unavailable to growers of fresh market tomatoes.